Process of making electric brushes.



No. 70!,363. Patented June 3, I902.

R. D. LAUGHLIN.

PROCESS OF MAKING ELECTRIC BRUSHES.

(Application filed Dec. 30, 1901.)

(No Model.)

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f? in v 6 Tot o-I W WM 43*. 11 W UNITED STATES PATENT OFFICE.

ROBERT D. LAUGIILIN, OF RAVENNA, OHIO, ASSIGNOR TO NATIONAL CARBONCOMPANY, OF CLEVELAND, OHIO, A CORPORATION OF NEN JERSEY.

PROCESS OF MAKING ELECTRIC BRUSHES.

SPECIFICATION forming part of Letters Patent No. 701,363, dated June 3,1902.

Application filed December 30,1901. Serial No. 87,674. (No model-3 Toall whom it may concern.-

Be it known that I, ROBERT D. LAUGI-ILIN, a citizen of the UnitedStates, residing at Ravenna, in the county of Portage and State of Ohio,have invented certain new and useful Improvements in Processes of MakingElectric Brushes, of which the following is a full, clear, and exactdescription, reference being had to the accompanying drawings.

The invention relates to electric brushes made of carbon and metallicwire, which brushes are especially adapted for use with electricdynamos, electric motors, electric contacts and circuit-breakers, andother electrical appliances. The object is to cheaply produce anexceedingly efficient electric brush of the character specified which isnot liable to become warped or cramped during the manufacture thereof,especially during the baking thereof.

The invention consists of an electric brush composed of a mass of bakedcarbon in which are embedded a plurality of separated wires runninglongitudinally only through the brush; and it also consists in theprocess hereinafter described for the construction of such brushes.

In the drawings, Figure 1 is a perspective view of one of the completedbrushes. Fig. 2 is a perspective view of one of the wirewoundgreen-carbon plates used in the manufacture of said brushes. Fig. 3 is aperspective View of one of the green-carbon plates, such as is used forthe two outer layers of carbon in constructing the brushes and which arepreferably used intermediate of the plates shown in Fig. 2. Fig. 4 is aperspective view of a slightly-modified form of one of the plates onwhich the wire is wound. Fig. 5 is an end View of a brush'in which theplates shown in Fig. 4 are used before the plates are compressedtogether. Fig. 6 is a plan view, and Fig. '7 a sectional View, of abox-mold in which the several constituent parts of the plate are pressedtogether.

Referring to the parts by letters, A represents a plateof green carbon,which is preferably formed by forcing plastic carbon through suitabledies, thereby forming ribbons of the required thickness and width, whichribbons are subsequently cut to the desired length. This method ofproducing the plates is a well-known method of producing similar platesand is not a part of the present invention. The plates may be producedotherwise, if desired. On some of these platcs-as, for example, theplate A (shown in Fig. 2) copper wire D of the desired gage is woundspirally but longitudinally of the plates, substantially as shown. Tomake the brushes, the plates A (shown in Fig. 3) and the wirewoundplates A (shown in Fig. 2) are alternately laid together, the outermostplates 011 both sides of the pile being without wires, and the pile isplaced in a mold-frame B, into which pressure-plates C C are fitted.Suitable pressure is applied to these plates to unite the carbon platesA and A into a homogeneous mass of carbon, in which these longitudinalwires are embedded. This being accomplished, the brushes are then bakedin the usual ovens, and thereby completed. Before they are used,however, the ends are preferably ground off, thereby removing the wireloops at the ends of the brushes, which connect the respectivelongitudinal strands of the wire.

Instead of making the brushes in precisely the manner above describedgreen-carbon plates substantially like those shown in Fig. 4 may beused, these plates having longitudinal grooves a on their sides toreceive the wire, whose diameter should be less than the depth of saidgrooves. The wire is wound spirally upon these grooved plates, the wiresbeing drawn into the grooves, and a plurality of plates with the wire sowound upon them are piled (shown in Fig. 5) between two plain plates A.The brush so made up in its green state is placed in the moldandsubmitted to pressure until the carbon becomes a homogeneous mass, andthe resultant structure is baked, as before explained.

Having described my invention, I claim- The herein-described process ofmaking electric brushes which consists in winding In testimony whereof Ihereunto affix my signature in the presence of two witnesses.

ROBERT D. LAUGHLIN.

W'itnesses:

H. L. BEATTY, Amos N. BARRON.

